Image viewer fullscreen error

[jrdh]

Description
When opening an image in LIV full screen it works, but then as soon as you pan, the screen goes black. You can exit out of it but then the image viewer (i.e. OpenSeadragon) just doesn't work anymore.

Expected Behaviour
Fullscreen should work.

To Reproduce

1. Go to https://data.nhm.ac.uk/image-viewer/record/05ff2255-c38a-40c9-b657-4ccb55ab2feb/10091736
2. Click on the one available record
3. Click on the fullscreen button in the viewer
4. Attempt to pan (you may need to zoom and then pan potentially if it doesn't immediately break)
5. Press escape to get out of the black screen
6. Click on the only available record in the list again
7. The image viewer part of the view is now completely gone

Error Log
No error shows when the viewer goes black, but this error shows at step 6 -> 7 above:

Your Setup
This is currently doing this on production. I've tried in Vivaldi and Firefox and get the same result.